Hello, I just noticed, how polygonal order in centerline (surface + cave polygons) can change the denivelation of the cave. Here are examples of the same data in different order. (Maybe I am doing something wrong?) :: ______ RIGHT DENIVELATION: (42 m lenght, 6 m den.) centerline date 2014.4.4 units tape cm data normal from to compass clino tape right left up down flags not surface p4 p5 33.6 -0.4 362 [0.3 0.1] [0.3 0.1] [0.9 3] [0.8 0.5] 4 5 180.6 -0.3 270 [0.4 0.6] [0.4 1.3] [0 1.5] [0.4 0.7] 5 6 140.3 -4.9 777 0.5 0.1 0.4 0.5 6 7 224 11 43 0.1 0.1 0.1 0.1 7 8 144.1 1.2 1011 0 0.4 0.3 0.3 1 2 141.2 -23.1 765 [4 4.1] [2 1.7] [0.5 6] [1 0.4] 2 3 157.4 -0.9 1015 1.4 1.2 0.2 0.3 data normal from to compass clino tape flags surface p7 p8 277.4 -39.3 1769 p8 - 148 0 700 p8 p9 172.6 14.5 2075 p9 J1 65.5 -10.2 126 2S p1 172.6 21.4 2087 p1 p2 34.7 31.8 1988 p2 p3 8.9 11.1 841 p3 J4 12.2 -29.8 388 p3 p4 137.3 17.4 1635 p6 p7 272.4 -22.6 521 p7 1 167.2 -17.5 295 p4 p6 188.7 1.1 3872 p6 4 186.1 -7.5 208 endcenterline ______ WRONG DENIVELATION: (42 m lenght, 13 m den.) centerline date 2014.4.4 units tape cm data normal from to compass clino tape flags surface p7 p8 277.4 -39.3 1769 p8 - 148 0 700 p8 p9 172.6 14.5 2075 p9 J1 65.5 -10.2 126 2S p1 172.6 21.4 2087 p1 p2 34.7 31.8 1988 p2 p3 8.9 11.1 841 p3 J4 12.2 -29.8 388 p3 p4 137.3 17.4 1635 p6 p7 272.4 -22.6 521 p7 1 167.2 -17.5 295 p4 p6 188.7 1.1 3872 p6 4 186.1 -7.5 208 data normal from to compass clino tape right left up down flags not surface p4 p5 33.6 -0.4 362 [0.3 0.1] [0.3 0.1] [0.9 3] [0.8 0.5] 4 5 180.6 -0.3 270 [0.4 0.6] [0.4 1.3] [0 1.5] [0.4 0.7] 5 6 140.3 -4.9 777 0.5 0.1 0.4 0.5 6 7 224 11 43 0.1 0.1 0.1 0.1 7 8 144.1 1.2 1011 0 0.4 0.3 0.3 1 2 141.2 -23.1 765 [4 4.1] [2 1.7] [0.5 6] [1 0.4] 2 3 157.4 -0.9 1015 1.4 1.2 0.2 0.3 endcenterline _________ WRONG DENIVELATION: (42 m lenght, 25 m den.) centerline date 2014.4.4 units tape cm data normal from to compass clino tape flags surface 2S p1 172.6 21.4 2087 p1 p2 34.7 31.8 1988 p2 p3 8.9 11.1 841 p3 J4 12.2 -29.8 388 p3 p4 137.3 17.4 1635 data normal from to compass clino tape right left up down flags not surface p4 p5 33.6 -0.4 362 [0.3 0.1] [0.3 0.1] [0.9 3] [0.8 0.5] data normal from to compass clino tape flags surface p4 p6 188.7 1.1 3872 p6 4 186.1 -7.5 208 data normal from to compass clino tape right left up down flags not surface 4 5 180.6 -0.3 270 [0.4 0.6] [0.4 1.3] [0 1.5] [0.4 0.7] 5 6 140.3 -4.9 777 0.5 0.1 0.4 0.5 6 7 224 11 43 0.1 0.1 0.1 0.1 7 8 144.1 1.2 1011 0 0.4 0.3 0.3 data normal from to compass clino tape flags surface p6 p7 272.4 -22.6 521 p7 1 167.2 -17.5 295 data normal from to compass clino tape right left up down flags not surface 1 2 141.2 -23.1 765 [4 4.1] [2 1.7] [0.5 6] [1 0.4] 2 3 157.4 -0.9 1015 1.4 1.2 0.2 0.3 data normal from to compass clino tape flags surface p7 p8 277.4 -39.3 1769 p8 - 148 0 700 p8 p9 172.6 14.5 2075 p9 J1 65.5 -10.2 126 endcenterline ________ Paľo Herich